<?php
/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: Mcrypt.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @see Zend_Filter_Encrypt_Interface
 */
require_once 'Zend/Filter/Encrypt/Interface.php';

/**
 * Encryption adapter for mcrypt
 * @category Zend
 * @package Zend_Filter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
class Zend_Filter_Encrypt_Mcrypt implements Zend_Filter_Encrypt_Interface {

    /**
     * Definitions for encryption
     * array(
     * 'key' => encryption key string
     * 'algorithm' => algorithm to use
     * 'algorithm_directory' => directory where to find the algorithm
     * 'mode' => encryption mode to use
     * 'modedirectory' => directory where to find the mode
     * )
     */
    protected $_encryption = array('key' => 'ZendFramework', 'algorithm' => 'blowfish', 'algorithm_directory' => '', 'mode' => 'cbc', 'mode_directory' => '', 'vector' => null, 'salt' => false);

    /**
     * Internal compression
     * @var array
     */
    protected $_compression;

    protected static $_srandCalled = false;

    /**
     * Class constructor
     * @param string|array|Zend_Config $options Cryption Options
     */
    public function __construct ($options) {
        if ( ! extension_loaded ('mcrypt')) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('This filter needs the mcrypt extension');
        }
        if ($options instanceof Zend_Config) {
            $options = $options -> toArray ();
        } elseif (is_string ($options)) {
            $options = array('key' => $options);
        } elseif ( ! is_array ($options)) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('Invalid options argument provided to filter');
        }
        if (array_key_exists ('compression', $options)) {
            $this -> setCompression ($options['compression']);
            unset ($options['compress']);
        }
        $this -> setEncryption ($options);
    }

    /**
     * Returns the set encryption options
     * @return array
     */
    public function getEncryption () {
        return $this -> _encryption;
    }

    /**
     * Sets new encryption options
     * @param string|array $options Encryption options
     * @return Zend_Filter_File_Encryption
     */
    public function setEncryption ($options) {
        if (is_string ($options)) {
            $options = array('key' => $options);
        }
        if ( ! is_array ($options)) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('Invalid options argument provided to filter');
        }
        $options = $options + $this -> getEncryption ();
        $algorithms = mcrypt_list_algorithms ($options['algorithm_directory']);
        if ( ! in_array ($options['algorithm'], $algorithms)) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ("The algorithm '{$options['algorithm']}' is not supported");
        }
        $modes = mcrypt_list_modes ($options['mode_directory']);
        if ( ! in_array ($options['mode'], $modes)) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ("The mode '{$options['mode']}' is not supported");
        }
        if ( ! mcrypt_module_self_test ($options['algorithm'], $options['algorithm_directory'])) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('The given algorithm can not be used due an internal mcrypt problem');
        }
        if ( ! isset ($options['vector'])) {
            $options['vector'] = null;
        }
        $this -> _encryption = $options;
        $this -> setVector ($options['vector']);
        return $this;
    }

    /**
     * Returns the set vector
     * @return string
     */
    public function getVector () {
        return $this -> _encryption['vector'];
    }

    /**
     * Sets the initialization vector
     * @param string $vector (Optional) Vector to set
     * @return Zend_Filter_Encrypt_Mcrypt
     */
    public function setVector ($vector = null) {
        $cipher = $this -> _openCipher ();
        $size = mcrypt_enc_get_iv_size ($cipher);
        if (empty ($vector)) {
            $this -> _srand ();
            if (strtoupper (substr (PHP_OS, 0, 3)) === 'WIN' && version_compare (PHP_VERSION, '5.3.0', '<')) {
                $method = MCRYPT_RAND;
            } else {
                if (file_exists ('/dev/urandom') || (strtoupper (substr (PHP_OS, 0, 3)) === 'WIN')) {
                    $method = MCRYPT_DEV_URANDOM;
                } elseif (file_exists ('/dev/random')) {
                    $method = MCRYPT_DEV_RANDOM;
                } else {
                    $method = MCRYPT_RAND;
                }
            }
            $vector = mcrypt_create_iv ($size, $method);
        } else 
            if (strlen ($vector) != $size) {
                require_once 'Zend/Filter/Exception.php';
                throw new Zend_Filter_Exception ('The given vector has a wrong size for the set algorithm');
            }
        $this -> _encryption['vector'] = $vector;
        $this -> _closeCipher ($cipher);
        return $this;
    }

    /**
     * Returns the compression
     * @return array
     */
    public function getCompression () {
        return $this -> _compression;
    }

    /**
     * Sets a internal compression for values to encrypt
     * @param string|array $compression
     * @return Zend_Filter_Encrypt_Mcrypt
     */
    public function setCompression ($compression) {
        if (is_string ($this -> _compression)) {
            $compression = array('adapter' => $compression);
        }
        $this -> _compression = $compression;
        return $this;
    }

    /**
     * Defined by Zend_Filter_Interface
     * Encrypts $value with the defined settings
     * @param string $value The content to encrypt
     * @return string The encrypted content
     */
    public function encrypt ($value) {
        // compress prior to encryption
        if ( ! empty ($this -> _compression)) {
            require_once 'Zend/Filter/Compress.php';
            $compress = new Zend_Filter_Compress ($this -> _compression);
            $value = $compress -> filter ($value);
        }
        $cipher = $this -> _openCipher ();
        $this -> _initCipher ($cipher);
        $encrypted = mcrypt_generic ($cipher, $value);
        mcrypt_generic_deinit ($cipher);
        $this -> _closeCipher ($cipher);
        return $encrypted;
    }

    /**
     * Defined by Zend_Filter_Interface
     * Decrypts $value with the defined settings
     * @param string $value Content to decrypt
     * @return string The decrypted content
     */
    public function decrypt ($value) {
        $cipher = $this -> _openCipher ();
        $this -> _initCipher ($cipher);
        $decrypted = mdecrypt_generic ($cipher, $value);
        mcrypt_generic_deinit ($cipher);
        $this -> _closeCipher ($cipher);
        // decompress after decryption
        if ( ! empty ($this -> _compression)) {
            require_once 'Zend/Filter/Decompress.php';
            $decompress = new Zend_Filter_Decompress ($this -> _compression);
            $decrypted = $decompress -> filter ($decrypted);
        }
        return $decrypted;
    }

    /**
     * Returns the adapter name
     * @return string
     */
    public function toString () {
        return 'Mcrypt';
    }

    /**
     * Open a cipher
     * @throws Zend_Filter_Exception When the cipher can not be opened
     * @return resource Returns the opened cipher
     */
    protected function _openCipher () {
        $cipher = mcrypt_module_open ($this -> _encryption['algorithm'], $this -> _encryption['algorithm_directory'], $this -> _encryption['mode'], $this -> _encryption['mode_directory']);
        if ($cipher === false) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('Mcrypt can not be opened with your settings');
        }
        return $cipher;
    }

    /**
     * Close a cipher
     * @param resource $cipher Cipher to close
     * @return Zend_Filter_Encrypt_Mcrypt
     */
    protected function _closeCipher ($cipher) {
        mcrypt_module_close ($cipher);
        return $this;
    }

    /**
     * Initialises the cipher with the set key
     * @param resource $cipher
     * @throws
     *
     *
     *
     *
     *
     * @return resource
     */
    protected function _initCipher ($cipher) {
        $key = $this -> _encryption['key'];
        $keysizes = mcrypt_enc_get_supported_key_sizes ($cipher);
        if (empty ($keysizes) || ($this -> _encryption['salt'] == true)) {
            $this -> _srand ();
            $keysize = mcrypt_enc_get_key_size ($cipher);
            $key = substr (md5 ($key), 0, $keysize);
        } else 
            if ( ! in_array (strlen ($key), $keysizes)) {
                require_once 'Zend/Filter/Exception.php';
                throw new Zend_Filter_Exception ('The given key has a wrong size for the set algorithm');
            }
        $result = mcrypt_generic_init ($cipher, $key, $this -> _encryption['vector']);
        if ($result < 0) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception ('Mcrypt could not be initialize with the given setting');
        }
        return $this;
    }

    /**
     * _srand() interception
     * @see ZF-8742
     */
    protected function _srand () {
        if (version_compare (PHP_VERSION, '5.3.0', '>=')) {
            return;
        }
        if ( ! self::$_srandCalled) {
            srand ((double) microtime () * 1000000);
            self::$_srandCalled = true;
        }
    }

}
